Proceedings of the International scientific and practical conference “Science in the Modern World” (January 19-21, 2026) / Publisher website: www.naukainfo.com. - Cambridge, United Kingdom, 2026. - 203 p.

106 ontogenesis [1, p. 1972; 2, p. 80]. Disorders of thyroid gland function, especially under conditions of emotional load, can significantly alter learning processes, memory, and anxiety levels [3, p. 455; 4, p. 110]. In this regard, studying the role of thyroid hormones in the formation of defensive spatial memory in the juvenile period is of particular relevance. Materials and Methods. The study was conducted on 60 sexually immature Wistar rats. Experimental hyperthyroidism and hypothyroidism were induced by administering L-thyroxine (Germany) at a dose of 3 μg/day or mercazolil (Ukraine) at a dose of 100 mg/kg with food for two weeks. Emotional load (EL) consisted of placing animals daily for 5 minutes in water at 21 °C for five sessions (chronic), as well as a single 5-minute exposure in a confined space of 1 m × 1 m (acute). Spatial memory was assessed using the Morris water maze by determining the latency to find the escape platform and the duration of the first freezing episodes, which serve as an indicator of anxiety [5, p. 48]. Animals were tested three times: after induction of experimental hyper- and hypothyroidism (first session), after chronic emotional stress (second session), and after acute emotional stress (third session). Results. Experimental hyperthyroidism in juvenile rats was accompanied by improved cognitive activity. In particular, the time required to find the escape platform in the Morris maze during three training sessions was shorter than in intact controls by 29%, 44%, and 38%, respectively. At the same time, the duration of the first freezing episodes was 2-2.2 times longer than in controls, which can be interpreted as a state of rational anxiety [3, p. 458]. Emotional load under experimental hyperthyroidism eliminated the mnemonic effect and was accompanied by a marked increase in anxiety. The duration of the first freezing episodes in the Morris maze was 4.4 times longer under chronic emotional load and 8.9 times longer under acute emotional load compared with the “EL” control.